In the field of breast cancer, stereotactically guided and percutaneous biopsy procedures have increased in frequency as well as in accuracy as modern imaging techniques allow the physician to locate lesions with ever increasing precision. However, for a given biopsy procedure, a subsequent examination of the biopsy site is very often desirable.
For example, in those cases where the lesion is found to be benign, a follow-up examination of the biopsy site may be conducted at a later time. Where the lesion is found to be malignant, the physician may want to place additional site markers to help guide the surgeon to the malignancy.
A number of procedures and devices for marking and locating particular tissue locations are known in the prior art. For example, location wire guides are well known for locating lesions, particularly in the breast. One such known device includes a tubular introducer needle and an attached wire guide, which has at its distal end, a helical coil configuration for locking into position about the targeted lesion. The needle is introduced into the breast and guided to the lesion site using an imaging system of a known type, for example, X-Ray, ultrasound or magnetic resonance imaging (MRI), at which time the helical coil at the distant end is deployed about the lesion. Then, the needle may be removed from the wire guide, which remains locked in position distally about the lesion for guiding a surgeon down the wire to the lesion site during subsequent surgery. While such a location system is effective, it is obviously intended and designed to be only temporary, and is removed once the surgery or other procedure has been completed.
It is also known to employ biocompatible dyes or stains to mark breast lesions. First, a syringe containing the colorant is guided to the detection lesion, using an imaging system. Later, during the extraction procedure, the surgeon harvests a tissue sample from the stained tissue. However, while such staining techniques can be effective, it is difficult to precisely localize the stain. Also, the stains are difficult to detect fluoroscopically and may not always be permanent.
Additionally, it is known to implant markers directly into a patient's body using an invasive surgical technique. This enables a practitioner to later return to the site of the graft by identifying the rings, for evaluation purposes.
Each of the above systems and methods for marking a biopsy site has disadvantages associated with effectiveness, accuracy, and invasive surgical techniques. Accordingly, what is needed is a site marker delivery system for delivering a marker to a biopsy site, and deploying the marker at the site effectively, accurately, and without the need for additional invasive surgical procedures.